In Windows environment (XP Pro), I downloaded JBoss 4.2.1.GA zip file. Unzip the server and execute the run.bat. It is giving me a Java exception, stating Port 4445 is already in use. What is this? It appears the server did start up.

I used netstat -o but it did not show port 4445 was used. I noticed that port 4445 was defined in the jboss-service.xml out-of-the-box. I also added ReservedPorts to the registry with value 4445-4445. After rebooting the machine, I am still getting the same error.

Check to see if you are running a service called enstart.exe. If so, your company is running Encase Enterprise Edition and there is no way you are going to get Encase to stop using 4445 unless your support staff is willing to change it. I would change your jboss serverbindport to something else.